Pulsfolge

Pulsfolge, or pulse sequence, refers to an ordered series of pulses produced for a particular purpose. It describes the timing, duration, amplitude and repetition of the individual pulses. A pulse sequence is defined by parameters such as pulse width, pulse repetition interval, duty cycle, amplitude and often phase. The spectrum of a pulse sequence is determined by these parameters; shorter pulses broaden the spectral content, while longer pulses concentrate energy in narrower bands.

Applications span several fields. In digital communications and signal processing, pulse sequences encode information through modulation techniques such as pulse-width modulation, pulse-position modulation and pulse-amplitude modulation. In measurement and imaging systems, sequences of pulses excite a medium and generate responses or echoes. In MRI and NMR, a pulse sequence refers to the prescribed timing of radiofrequency and gradient pulses used to manipulate spin magnetization, producing contrast and spatial encoding; common examples include spin-echo and gradient-echo sequences. In ultrasound, sequences of acoustic pulses form images. In power electronics and control, pulsed sequences regulate switching devices and implement PWM schemes.